[PATCH] mm: code improvement of check_stack_guard_page

[jovi zhang]

little code improvement of check_stack_guard_page function.
this commit is on top of commit "mm: keep a guard page below a
grow-down stack segment" of linus.

diff --git a/mm/memory.c b/mm/memory.c
index 9b3b73f..643b112 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2768,13 +2768,15 @@ out_release:
 */
Âstatic inline int check_stack_guard_page(struct vm_area_struct *vma,
unsigned long address)
Â{
-ÂÂÂÂÂÂ address &= PAGE_MASK;
-ÂÂÂÂÂÂ if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ address -= PAGE_SIZE;
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ if (find_vma(vma->vm_mm, address) != vma)
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return -ENOMEM;
-
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ expand_stack(vma, address);
+ÂÂÂÂÂÂ if (vma->vm_flags & VM_GROWSDOWN) {
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ address &= PAGE_MASK;
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ if(address == vma->vm_start) {
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ address -= PAGE_SIZE;
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ if (unlikely(find_vma(vma->vm_mm, address) != vma))
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return -ENOMEM;
+
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ expand_stack(vma, address);
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ }
ÂÂÂÂÂÂÂ }
ÂÂÂÂÂÂÂ return 0;
Â}
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